I don't understand the question.
If you die there is a final tax return done in the year of death and then the estate does the tax return for itself until the assets are passed.
If you die with a large portfolio and pass these on then the beneficiary won't pay CGT until those properties are sold. However you cannot pass on loans. So a beneficiary would have to apply to a bank to keep the loans at the same amount or the loans will need to be paid out by the estate or by the beneficiary. Depends on the terms of the will. Loans have no effect on CGT generally.
If your mum owned property and passed them onto you the tax would only be payable when they are sold. You will generally inherit her cost base, unless it was the main residence in which you will inherit the cost base at the time of death.
If the estate sold them then the estate would pay the CGT. If the debt is more than the assets of the estate then it will be insolvent. This doesn't fall into the hands of beneficiaries but stops there.
Ok sorry, I was confusing
I'll put it bluntly
Im looking at two strategies with the least possible tax
1. Spend all my equity away while I'm alive ie refinance just before I die, spend it all, give it to kids, buy property in their name, when I die, everything gets sold off, and I'll have pretty much zero left, but then I'll get a huge cgt bill but the debt will die with me
2. Spend little, gets passed onto my kids with zero tax upon transfer upon my death, is this possible, so kids inherit portfolio with low lvr, and can rely on future cg